I haven`t played for a while, so I might be a bit fuzzy on some details.
The Iconians have a super ability, Super Adapters, which gives them those techs. Its very purpose to to ensure that they can colonize some kinds of extreme worlds on the first turn. The Yor get Barren worlds as part of their super ability, Super Isolationists. The Torians can research Aquatic worlds early on and cheaper too. So, there are a number of different reasons why a civ might have access to some worlds early on.